That the hidden strength of Facebook is its marketing data, not necessarily its ad media.

And that Facebook hasn't even begun to tap into that yet.

Yet, even without bringing the totality of the customer data that Facebook owns to the party, Zappos still gets a 3.5 to 1 return on ad dollars spent on the social network.

Here are Lurman's two key quotes. First, on the advertising ROI :

"Facebook ads work for us. We've spent about $10 million over the past two years at about a 3.5:1 ROI. About 99 percent of that spend has gone toward direct-response ads driving traffic to Zappos.com."

Shoes aren't cars, of course. So perhaps it is unreasonable to expect high-consideration purchase clients like GM to get the kind of results Zappos does. But still, it appears the company has "figured out" Facebook advertising.

Second, on the data:

"Getting users to authorize data share beyond the basic profile information opens you up to the ability to bridge the gap between Facebook data and outside initiatives, but I have yet to see anyone tap into this data in an impactful customer-facing way."

That last sentence ought to be considered carefully for what it implies: Zappos is getting a 250 percent return on its money now, and that's before Facebook turns on its hidden data machine. Imagine what that might be like once the engine is really fired up.